Automatic firearm



Dec. 6, 1960 H. UPPER-r ETAL 2,962,936

AUTOMATIC FIREARM Filed May 26, 1958 2 Sheets-Sheet 1 In Venfors H. L//o/Per?" E. NLM/Hmmm Dec.. 6, 1960 H. LIPPERT ETAL AUTOMATIC FIREARM Filed May 26, 1958 Fig.9

[0 venrs Lf/ofserf 5MM/2mm senese Patented Dec. 6, 1960 minoritario r f:

Hans Lippert, Kiiehberg, Zurich, and Ernst Mhlernann, Zurich, Switzerland, assignors to Machine 'liool Works @ei-litten, Administration Company, Znrich-erlilron, Switzerland, a company of Switzerland The invention relates to an automatic rearrn having a xed barrel and a breech mechanism comprising a receiver, a breech body and a percussion pin carrier. The breech body, which supports the pressure of the cartridge base, as well as the percussion pin carrier, are mounted longitudinally shiftable in the receiver. The spring biased percussion pin carrier, which is also shiftable relative to the breech body controls the locking of the latter in the ring position by a member guided on guide faces in the receiver. After tiring, the percussion pin carrier is pushed back relative to the breech body by a gas piston, thereby unlocking the breech body.

Such firearms have become known under the term of rigidly iocked gas pressure loaders. In the known systems of this kind the member guided by guide faces in the receiver is designed as a locking member proper which supports the breech body in its ring position against the receiver. These locking members have to be dimensioned strongly corresponding to the large forces occurring and are therefore comparatively weighty. Since they form part of the moving mass of the breech mechanism, the same becomes also comparatively heavy.

it is a primary object of the present invention to provide a firearm of the rigidly locked gas pressure loader type, wherein the locking member proper does not take part in the recoil movement of the breech body and wherein accordingly the member guided by the guide faces in the receiver is of light weight and low inertia.

With this and other objects in view, which will become apparent later from this specification and the accompanying drawings, we provide an automatic firearm comprising in combination: a fixed barrel, a receiver in alignment with and iixedly connected to said barrel, a breech mechanism mounted longitudinally movably in said receiver, said breech mechanism having a breech body taking the pressure of the cartridge base, a percussion pin carrier shiftable relative to said breech body, a closing spring biasing said percussion pin carrier against said breech body, a controi member guided by guide faces in said receiver controlling the locking of said breech body in the firing position, a gas cylinder in communication with said barrel, a gas piston movable in said gas cylinder and in operative contact with said percussion pin carrier so as to push the same after the firing of the shot back from its tiringand locking-position against the bias of said closing spring, said control member being a transverse yoke lying across the axis of said breech mechanism, mounted in said percussion pin carrier slidably perpendicular to the direction of movement thereof, guided in oblique slots in said breech body, and with its ends engaging into longitudinal solts enlarged at their forward ends in the said receiver, and at least one locking body having two arms mounted in said receiver, one arm of said locking body supporting said breech body in its locked position, and the other arm thereof being operatively controlled and underpinned in the locking position by said transverse yoke.

These and other features of our invention will be clearly understood from the following description of two embodiments thereof given by way of example with reference to the accompanying drawings, in which:

Fig. 1 diagrammatically shows a section on a vertical plane containing the axis of a firearm according to a rst embodiment, with the breech mechanism in the tiring position;

Fig. 2 is a section on a larger scale on a horizontal plane through the breech mechanism, at the beginning of the locking thereof;

Fig. 3 corresponds to Fig. 2, however at the beginning of the relative movement between the Vpercussian pin carrier and the breech body;

Fig. 4 corresponds to Fig. 2, however in the tiring position, after completion of the locking of the breech body and underpinning of the locking bodies;

Figs. 5-8 show the transverse yoke in various positions, namely:

Fig. 5 in the catching position of the breech;

Fig. 6 in the breech position according to Fig. 2;

Fig. 7 in the breech position according to Fig. 3;

Fig. 8 in the breech position according to Fig 4;

Figs. 9-13 show a second embodiment of the invention, namely:

Fig. 9 a horizontal section of the firearm at the moment of tiring;

Fig. l() is a vertical section through the breech mechanism on the line X-X of Fig. 9;

Fig. ll a section on the line X'I-XI of Fig. 9;

Fig. 12 a section on the line XII-XH of Fig. l0;

Fig. 13 a cross section on a larger scale through the control slots of the breech body and the transverse yoke moving therein.

In Fig. l the barrel is denoted by 1, which is inserted by means of a bayonet joint 2 in known manner into the receiver 3, and wherein moreover the breech mechanism consisting of the breech body 4, percussion pin carrier 5 and transverse yoke 6 is mounted longitudinally shiftably. The carrier 5 is shiftable in a cavity 41 provided in the breech body 4 and extending along the axis of the barrel 1. The breech body is moved into the firing position by means of the closing spring 7 preloaded between the percussion pin carrier 5 and the receiver 3. In the cylinder chamber 9 of the receiver a gas piston 1t) is housed which is moved by the gas passed in the usual manner through a port 8 from the interior of the barrel into this cylinder, and which is in driving connection with the percussion pin carrier 5 by means of the rod 11 connected therewith. A sear mechanism for the breech mechanism is denoted by 12.

According to Fig. 2, two locking bodies 13 in the form of two-armed levers are pivotally mounted on pins 14 fixed in lateral bulges of the receiver 3. One arm 13a of these locking bodies serves for controlling and securing the same, and the other arm 13b thereof for locking the breech body in the firing position. The locking bodies are swung inwardly by the oblique faces 6b of the transverse yoke 6 towards their locking position. This closing movement takes place for example against the bias of springs 15 acting in the direction of an opening movement of the locking bodies and tending to turn the same out of the path of the breech.

In the firing position the breech body 4 engages the base of the cartridge 16 located in the cartridge chamber of the barrel and is locked by the locking bodies resting on abntments 4a near the forward end of the breech body. In the side walls 4b control slots 17 in the form of oblong openings are cut out for the transverse yoke 6 which as seen in Fig. 5 extend obliquely from top to bottom. The slope of these slots 17 conforms with the cross Section profile of the transverse yoke 6, while their height amounts approximately to twice the heightof the latter.

The percussion pin carrier is guided between the side Walls 4b in the cavity 41 of the breech body 4, and the firing pin 5a connected therewith is guided in abore 4d of the breechA body. Perpendicular to the axis of the weapon arectangular slot 19 is machinedvinto the percussion pin carrier, which slot is at least as wide as the control member 6 and is Vdimensioned so high that the same can move unhampered from the highest to the lowest point of the control slot 17 in the breech body. v

The transverse yoke 6 penetrates through the breech body 4 and the percussion pin carrier 5 in a direction perpendicular' to the axis of the weapon, and is for example of a hexagonal cross section as illustrated inl Figs. 5 to 8, which prole isv determined by the mechanical stresses arising.' -On thelateral end faces of the transverse yoke 6 oblique faces 6b are arranged extending forward towards the middle of the weapon, which faces control theV locking bodies 13 Aby ruimingupon the oblique faces 13C thereof in the closing position, and the rear portion 6a of these end faces moves under the locking bodies and secures the same in this position. The control member is guided parallel to the axis of the barrel bya pair of guiding planesv formed by two slots 18 in the side walls of the receiver 3. The lower faces 18a of these slots serving as a safeguard extend parallel to the axis so far forward that the transverse yoke remains secured against a relative movement with respect to the breech body, until the same has reached theV firing position `(Fig."7). The forward ends of the slots are enlarged, as shown 6-8, so that the transverse yoke can move unhampered in the control slot 17 of the breech body when in the firing position, K Y, w

The movement of the transverse Vyoke 6' is diagrammatically illustrated in elevation in Figs. 5-'8. The transversel yoke is' hatched,'and the control slot 17 of the' breech body 4 is drawn in full lines. The guide slot 1S in the receiver is drawn in 7dotted lines, and the slot 19 in the percussion pin carrier in dot and dash lines.

The manner of operation of the breech mechanismcis asfollows: p

With the breech mechanism cocked (Fig. 5) the transverse yoke 6 rests on the guide faces 18a of the portion parallel to the axis of the slots 18 in the receiver, and abuts on the rear upper end of the control slot 17 in ,the breech body as well as on the upper end of the slot 19y in the percussion pin carrier 5. By this supporting of the transverse yoke 6 in the slots 18 of the receiver the same is prevented from sliding obliquely downward in the control slot 17, and from moving forward relative to the breech body, together with the percussion pin carrier 5 and the percussion pin 5a. After actuation of the Sear mechanism 12 the closure spring 7 housed -in the breech body 4 and acting on the percussion pin carrier( pushes the breech body forward, its force being transmitted to the transverse yoke 6 and further through the oblique face 6c thereof to the forward upper face 17a of the control slot and thereby to the breech body 4. In the course of the movement of the breech body with the locking bodies 13 open, a cartridge is fed in conventional manner (not shown) from a belt or magazine, and inserted into the cartridge chamber Vof the barrel. Shortly before the breech body has reached the tiring position, i.e. when it is yet a distance s behind this position (Figs. 2 and 6), the inclined faces 6b of the transverse yoke contact the oblique faces 13C of the locking bodies 13 and direct the same towards the locking position (Fig. 3) while covering the distance s.

`Until the most forward position of the breech body,

i.e. the tiring position, is reached, fin which thebree'ch body abuts the faces 20 ofthe receiver, the relativeposition of the percussion pin carrier 5, transverse yoke 6 and breech body 4 hasnotchanged. nThen the trans-A verse 'yoke enters into the enlargements of vthe slots 1,8 (Fig. 7) whereby the safeguarding is abolished, and since the breech body 4 stands still, it slides in the guide slots 17 forward and downward (Fig. 8). By this movement of the transverse yoke on the stretch z the locking bodies are completely swung into the closing position, and by the transverse yoke resting on their arms 13a they are underpinned and secured in this position (Fig. 4). At the same time the transverse yoke moves downward in the slot 19 of the percussion pin carrier. At the end of this forwardly directed movement of the percussion pin carrier and transverse yoke the percussion pin 5a fires the cartridge. The two locking bodies 13 take the gas forces applied to the cartridge and hence to the breech body VV4, whereby immediately after'the'fring` ofthe shot the unlocking process is linitiated in that the gases passing in the usual manner from the barrel into the cylinder space 9 move the piston 10 with the piston rod 11 rearwardly. This rod, acting on the extension 5b of the percussion pin carrier pushes the same back, whereby the transverse yoke 6 is moved rearward and upward in the control slot of thebreech body, which is still retained in the firing position, and removes the underpinning of the two locking bodies. v

The supporting faces 13d of the locking bodies are so designed that under, the action of rearwardly directed forces applied to them through the abutment faces 4a of theA breech body they impart an opening moment to the locking bodies whereby their arms 13b are swung out and the breech body is released. Under the action of the residual gases contained in the barrel thereafter the entire breech mechanism is thrown back, the transverse yoke 6 at the beginning of this recoil movement being again secured against any movement relative to the breech body by running upon the lower guide faces 18a of the slots 18 inthe receiver. During the recoil of the breech body the spent cartridge case is withdrawn in the usual manner by a withdrawer from the barrel and ejected downwardly from the weapon by an ejector. The loaded closing Y spring .throws the breech body again forward from its rear reversal point,` whereby a new cartridge is inserted into the barrel.

The design of the weapon described hereinabove forms only one possible embodiment which may be modified within the scope of the invention by many modifications, as shown for example in the Figs. '9-13. -In contrast to the embodiment illustrated in Figs. y1 8, which discloses more the principle of the invention, inthese Figs. 9-13 another design embodiment of a iirearm according to the invention is shown. The same will be described hereinafter supplementarily, as far as it differs from 'the embodiment described hereinabove. ,l

In the Figs.'9-l3 vthe receiver is denoted by v25, the barrel by 26, 'the breech body by 27, the percussion pin carrier by.28 and the transverse yokey by 291,., The locking bodies 30, actinglikewisel as two-armed levers and having supporting faces 30a extending over -theirk entire height, control faces 305 andV underpin faces Stic, `are designed as semi-cylinders the longitudinalaxes of which constitute their axes of rotation. On the'sliding and pressurefaces 30d constituting the circumference of the cylinder body, dovetail-shaped grooves 31 areY machined (Fig. ll) into which engage correspondingly shaped guide pieces `32, whichY secure the locking bodies, when the breech body has recoiled, against dropping out of their seats in the receiver. The locking bodies are secured in the open positionl by spring biased pinsv 33 `engaging into recesses 34.

The'breech body'27 isA slidably mounted in theguides 35 of the receiver 25 (Fig. l2). The control slots 317 are directed obliquely from below forwardly and upwardly, in contrast to the r'st embodiment of the firearm, so that the transverse yoke at the movement relative to the breechy body as required for the firingY position is directed upwardly by sliding on the faces 27b, 7c` thereof (Fig. 13,),y andthen rests on' the middle of fthe underpin faces 30C of the lockin'g'bodies 30. Y

The transverse yoke 29 is guided in the grooves 39 cut into the side walls of the receiver parallel to the axis of the weapon, and is secured by the upper faces 39a thereof against any upwardly directed movement in the control slot of the breech body. These guide faces 39a end at the point where the transverse yoke is located when the breech body has reached the tiring position.

On the forward stroke of the breech body, the breech body 27 is accelerated by the pressure imparted to it by the face 29a (Pig 13) of the transverse yoke 29, while conversely on the return stroke after the unlocking of the breech body the accelerating forces of the residual gases in the barrel are transmitted from the breech body 27 through the faces 27b thereof to the transverse yoke and hence to the percussion pin carrier. In view of the wedge action of the transverse yoke guided in the receiver, the inclination of these pressure faces 29a and 27b is made Vlarger than the inclination of the forwardlyeadjacent parts 27e of the control slots, in which the released transverse yoke performs merely the movement for the securing and releasing of the locking bodies.

The foot 28a of the percussion pin carrier slidably guided in the receiver reaches under the breech body 27, while the head 28h is inserted into a longitudinal groove thereof, which permits the movement to firing posit-ion of the percussion pin carrier 28 with the percussion pin 28e (Fig. 1o).

The oblique end faces 38 marked in dotted lines in Fig. 9 of that part of the breech body which rest on the guides 35 of the receiver transmit the first rotational impulse towards the closing position shown in Fig. 9 to the locking bodies by running upon the control faces 30b thereof, whereafter the transverse yoke completely turns the locking bodies into the closing position and locks the same therein.

The manner of operation of the embodiment of the firearm according to the invention illustrated by way of example in the Figs. 9-13 and supplementarily described hereinabove can besides be derived easily from the operation described with reference to the embodiment according to Figs. 1 to 8.

While we have described herein and illustrated in the accompanying drawings what may be considered typical and particularly useful embodiments of our invention,

we wish it to be understood that we do not limit ourselves to the details and dimensions described and illustrated; for obvious modifications will occur to a person skilled in the art.

What we claim as our invention and desire to secure by Letters Patent, is:

In an automatic firearm comprising in combination, a receiver provided with a pair of guiding planes extending in axial direction; a breech body axially displaceable in said receiver between a ring position and an unlocked position having an axial cavity and side walls, the latter standing opposite each other relative to the breech body axis and having abutments adjacent the front end of said breech body, said side walls further having a pair of openings positioned opposite each other relative to the breech body axis, said openings being parallel to each otherandinclined toward the breech bodyaxis; a spring-VV tensioned carrier guided by said side walls for axial displacement in said cavity and having a slot therein extending transversely to the breech body axis; a gas piston in driving connection with said carrier in order to push said carrier backwards against spring tension during firing; a yoke displaceable in said slot in a direction at right angles to the breech body axis and parallel to said side walls and extending through said openings, which upon a displacement of said carrier in said cavity of the breech body is shifted along said openings and which during an axial displacement of said breech body in said receiver outside said ring position is locked against a movement transverse to the breech body axis by said guiding planes; a pair of locking bodies pivoted to said receiver and in tiring position having their forward ends engaging said abutments and `their rear ends locked by said yoke to lock said breech body in firing position.

References Cited in the file of this patent FOREIGN PATENTS 641,356 Germany Jan. 28, 1937 535,570 Great Britain Apr. l5, 1941 232,646 Switzerland Sept. 1, 1944 418,577 Italy Feb. 24, 1947 

